Conventionally, iron complexes have been widely used for medical use, and in cosmetic preparations, photographs, information recording materials (magnetically recording materials, laser recording materials, etc.), copying materials (heat-sensitive materials and pressure-sensitive materials, etc.) and particularly have been used as an oxidizing agent utilized in the field of silver halide photosensitive material, for example, as a reducing agent for use in reducing processing of a silver halide photosensitive material and a bleaching agent for use in bleaching processing, in a large amount. An example of the iron complex which has be used as a bleaching agent in many times include ferric salt of ethylenediaminetetraacetic acid, but the bleaching ability thereof is not so high and is not enough when a rapid processing is required. On the other hand, red prussiate salt and ferric salt of 1,3-propanediaminetetraacetic acid are disclosed as iron complexes having a high bleaching ability, but due to their high oxidation-reduction electric potential, there is a tendency to accelerate the decomposition of co-existing compounds and, therefore, their applications have been restricted.
In addition, compounds comprising ethylenediamine-N,N'-diacetic acid-N,N'-dipropionic acid similar to the compound of the present invention have been known.
However, this complex has been found to possess the problem that its oxidation-reduction electic potential is changed by varying a pH level, and especially an oxidizing power is decreased at a high pH region.
Generally, a silver halide black-and-white photosensitive material after the exposure is processed through black-and-white development, fixation, water washing and any other processing stages, and a silver halide color photosensitive material (hereinafter referred to as "color photosensitive material") after the exposure is processed through color development, desilvering, water washing, stabilization and any other processing stages. A silver halide color reversal photosensitive material is processed after the exposure through black-and-white development, and after the reversal processing processed through processing stages such as color development, desilvering, water washing and stabilization.
In the color development, photosensitized silver halide grains are reduced to silver by a color developing agent and, at the same time, the formed oxidized product of the color developing agent is reacted with a coupler to form an image dye in the color developing stage. In the subsequent desilvering stage, the developed silver formed during the developing stage is oxidized (bleached) with a bleaching agent (oxidizing agent) having an oxidizing function to a silver salt, which is then removed from the photosensitive layer together with an unused silver halide, with a fixer which forms a soluble silver (fixation).
Concerning the bleaching and fixation, there are a case where a bleaching stage and a fixation stage are separately carried out and a case where they are carried out at the same time as a bleach-fixing stage. The details of these processing stages and compositions thereof are described in James, "The Theory of Photographic Process", 4th edition, (1977); Research Disclosure (RD) No. 17643, pages 28-29, RD No. 18716, page 651, from left column to right column, and RD No. 307105, pages 880-881, etc.
In addition to these basic processing stage, various supplemental stages are applied for the purpose of maintaining photographic and physical qualities of dye image, for the purpose of maintaining the stability of processing, etc. For example, water washing stage, stabilization stage, hardening stage, stopping stage, etc. can be mentioned.
In order to adjust gradation, etc. of a developed silver halide black-and-white photosensitive material, the material is processed with a reducing solution containing an oxidizing agent.
These processing stages are generally carried out by an automatic developing machine and the photographic processing is carried out at various locations from large scale developing centers which provide a large-size automatic developing machine, to photograph shops which provide in front of the shop a small-size automatic developing machine so-called "small-size laboratory" in recent years. This widens a service for rapid processing. However, ferric salt of ethylenediaminetetraacetic acid has, which has been conventionally used as a bleaching agent in a bleaching or bleach-fixing stage in the processing of a color photosensitive material, the basic problem of weak oxidizing power, in spite of making an improvement such as the use of a bleaching accelerator (e.g., the addition of a mercapto compound as described in U.S. Pat. No. 1,138,842), the object of rapid bleaching has not yet been attained.
As bleaching agents which attain rapid bleaching, red prussiate, iron chloride, bromates, etc. have been known. However, for red prussiate in terms of the problems associated with environmental safeguard, iron chloride in terms of inconvenience associated with handling such as metal corrosion, and bromates in terms of the problem associated with the instability of the solution, they cannot be widely used.
Consequently, it has been desired to provide a bleaching agent having good handing ability, free from the problems associated with the discharge of wasted liquid and attaining rapid bleaching. In recent years, ferric complex of 1,3-diaminopropanetetraacetic acid is disclosed as one which satisfies such requirements.
However, ferric complex of 1,3-diaminopropanetetraacetic acid has the problems in terms of ability that bleach fogging occurs accompanying with bleaching. As a process for reducing the bleach fogging, the addition of a buffer to the bleaching solution (e.g., JP-A-1-213657; the term "JP-A" used herein means Japanese unexamined patent publication). However, the level of the improvement is not sufficient and, particularly, in the color development carried out within three minutes, since a highly active developer is used, the generation of large bleach fogging still takes place.
When a processing solution comprising the ferric complex of 1,3-diaminopropanetetraacetic acid is used, there arise the problems that staining is increased during the storage after the processing, or when being continuously processed with the above processing solution there pose the problems that the desilvering properties are decreased in comparison with those at an initial continuous processing stage and that fogging takes place at an unexposed portion due to the mixing of the bleaching solution with the color developer.
Moreover, for carrying out the bleaching processing rapidly, a process using one bath (bleach-fixing bath) as a bleaching bath and a fixing bath has been known, but when the processing solution having a bleaching ability comprising ferric complex of 1,3-diaminopropanetetraacetic acid, ammonium thiophosphate, which is a fixer, is decomposed, thereby forming a precipitate to stain the surface of the photosensitive material and to cause the blockage of filter and poor desilvering.
On the hand, in accordance with the fact that the photographic processing is carried out at various locations from a large-scale developing centers which provide a large-size automatic developing machine to photograph shops which provide in front of the shop a small-size automatic developing machine so-called "small-size laboratory" in recent years, there is the problem that the processing ability of the processing solution in the above processing stage is decreased.
As one serious cause, mixing of the processing solution with metal ions can be mentioned. Various metal ions are mixed with the processing solution via various routes. For example, calcium, magnesium, and in some cases, iron ions are mixed with the processing solution through water for preparing the processing solution, and calcium contained in gelatine of the photosensitive material is mixed with the processing solution. Moreover, an iron chelate used in the processing solution is mixed with the developing solution, which is the pre-bath, by splashing the solution into the pre-bath, a solution having been impregnated in the film is carried over to carry over the ions contained in the pre-bath in some cases.
The influences of the mixed ions are different depending upon the types of ions and processing solutions.
Calcium and magnesium ions mixed with the developing solution are reacted with a carbonate generally used as a buffer to form a precipitate or sludge, causing the problems of blocking the circular filter of the automatic developing machine and staining of the film. The mixing of a transition metal ion such as iron ion with the developing solution causes the decomposition of parapheylanediamine type color developing agents and black developing agents such as hydroquinone and monolole and of preservatives such as hydroxylamines and sulfites, and the photographic properties are drastically deteriorated.
When a transition metal ion such as iron ion is mixed with a bleaching solution using hydrogen peroxide or a persulfate, also the stability of the solution is decreased, causing the problems associated with lacking in bleaching.
Also in the fixing solution, in the case of a fixing solution using a usual thiosulfate as a fixer, the mixing of a transition metal salt causes a drastic decrease in the stability, generating the muddiness in the solution and a sludge. As a result, due to the blockage of the filter of the automatic developing machine, an amount of flow circulated is decreased, the stability becomes lacking and processing staining is brought about on the film. Such phenomena in a fixing solution also take place in the washing water subsequent to the fixing solution, and particularly when an amount of washing water is decreased, an efficiency for exchanging the solution in the tank is decreased, which tends to cause the problems of the decomposition of a thiosulfate called sulfidation, and of the formation of a precipitate of the silver sulfide. These states often cause fatal staining on the surface of the film.
In a stabilizing solution prepared using hard water containing large amounts of calcium and magnesium, bacteria are generated taking these metals as nutrition resource, generating muddiness in the solution and causing film staining. In the case of mixing transition metal ions represented by iron ion, these ions remaining on the film change the storage ability for the worse.
As described above, the mixing of metal ions with processing solution causes various harmful effects and, thus, it has been strongly desired to provide an effective ion masking agent.
As means for solving these problems, a chelating agent which masks metal ions has been used. Examples include aminopolycarboxylic acids (e.g. ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid) as described in JP-B-48-30496 (the term "JP-B" used herein means Japanese examined patent publication) and JP-B-44-30232, organic phosphonic acids as described in JP-A-56-97347, JP-B-56-39359 and West German Patent 2,227,639, phosphonocarboxylic acids as described in JP-A-52-102726, JP-A-53-42730, JP-A-54-121127, JP-A-55-126241, and JP-A-55-65956, as well as compounds described in JP-A-58-195845, JP-A-58-203440 and JP-B-53-40900.
As a compound having a skeleton similar to that of the compound of the present invention, ethylenediaminediacetic acid dipropionic acid as described in "Journal of American Chemical Society", Vol. 74, page 6288 (1952) or Vol.75, page 4814, can be mentioned.
Although some of these compounds have been put into a practical use, their abilities are not sufficient. For example, ethylenediaminetetraacetic acid has a large masking power, against calcium ion but when being added to a developer, it accelerates the decomposition of a developing agent or a preservative for developing agent in the presence of iron ion, and causes deterioration in photographic properties such as decreased image density, and increased fogging. For example, although an alkylidenediphosphonic acid has no such an adverse influence even in the presence of iron ion, it causes the trouble that solid substances (tar) occur in a processing solution prepared from hard water containing a large amount of calcium, and causes a trouble of a developing machine. As compounds which solve the problems seen in these two compounds at the some time, chelating agents are described in JP-5-66527. However, these compounds are difficult to maintain their abilities under severe conditions such as heightening a processing temperature and extending a residence time in a processing solution.
Ethylenediaminediacetic acid dipropionic acid having a skeleton similar to that of the compound of the present invention have a large variation in masking ability according to a change in pH, and in the case of changing the conditions for a processing solution, their abilities are sometimes not in a sufficient level. Particularity, in an alkaline developing bath, since its iron ion masking power is originally low, an excess amount of this compound is required to be added, which is not preferable in terms of photographic properties. In particular, according to increased social requirements for environmental safeguard, an amount of replenishing a photographic processing solution tends to be decreased and, thus, a residence time of a developer in a processing machine becomes longer. From the viewpoint of a requirement for rapid processing, concentrations of developing agent, bleaching agent, and fixer become high and, thus, a temperature for processing tends to be high, the deterioration in storage ability increasingly becomes a serious problem.
As a concentration of a processing solution becomes high for the purpose of rapid processing, since a concentration of solution carried over to the next bath is high, the variations in conditions (chiefly pH) are increased. For this reason, the effect of a metal masking agent is disadvantageously thinned. Consequently, in particular it has been desired to develop an-excellent novel chelating agent which effectively masks deposited metal ions over a prolonged period without any trouble and with a little affection with variation in conditions.
Consequently, the first object of the present invention is to provide an iron complex having an appropriate oxidizing power and a little influence upon co-existing compounds.
The second object of the present invention is to provide an iron complex having a small change in the oxidizing power by the variation in pH.
The third object of the present invention is to provide a novel additive for photography which hardly affects photographic properties (especially, sensitivity and fogging).
The fourth object of the present invention is to provide a photographic processing composition without generation of any precipitate and sludge even when mixing a metal ion.
The fifth object of the present invention is to provide a stable processing composition without any decrease in effective components, without forming ineffective components and without forming any component having a photographically adverse effect even when mixing a metal ion.
The sixth object of the present invention is to provide a processing composition which can sufficiently maintain abilities even under severe conditions due to heightening a temperature of the processing composition and extending a residence period of a processing solution, and to provide a processing process using the same.
The seventh object of the present invention is to provide a processing composition which effectively masks deposited metal ions over a prolong period without any trouble and with a little affection with variation in conditions, even in a processing solution having high concentration, and to provide a processing process using the same.
The eighth object of the present invention is to provide a composition for processing a silver halide photosensitive material excelling in a desilvering property, particularity a processing composition having a bleaching ability, and to provide a processing method using the same.
The ninth object of the present invention is to provide a composition for processing a silver halide photosensitive material having a little bleach fogging, particularity a processing composition having a bleaching ability, and to provide a processing method using the same.
The tenth object of the present invention is to provide a composition for processing a silver halide photosensitive material having a little staining with the time elapse, particularity a processing composition having a bleaching ability, and to provide a processing method using the same.
The eleventh object of the present invention is to provide a composition for processing a silver halide photosensitive material which can stably maintain the abilities described above even when being continuously processed, particularity a processing composition having a bleaching ability, and to provide a processing method using the same.
The twelfth object of the present invention is to provide a bleach-fixing composition which is difficult to decompose a fixer and can maintain stable processing abilities when being used as a bleach-fixing, and to provide a processing process using the same.
The thirteenth object of the present invention is to provide a bleach-fixing composition which exhibits rapid desilvering property on running processing, which forms only a small amount of precipitate, and which is free of staining on the surface of a photosensitive material and of blockage of a filter, and to provide a processing process using the same.